<!DOCTYPE html>
<html>
    <head>
        <title>stylesheet</title>
        <style title="Hello">
            a::before {
                color: red;
                content: "Hello";
            }
        </style>
        <link ref="stylesheet" title="x" href="data:text/css,p%7Bcolor:blue%7D"/>
    </head>
    <body>
        <a>world</a>
    </body>

    <script>
        
    </script>
</html>